Height adjustable working table

ABSTRACT

The invention relates to a height adjustable working table ( 1 ) with two guide tracks ( 3 ) for mounting a working surface ( 2 ) which may adjusted for height by means of a drive motor ( 15 ) with cable pulleys and draw cables ( 13 ).

The invention relates to a height-adjustable working table with twoguide rails for receiving a worktop, which is adjustable in its workingheight by means of a drive motor with cable drums and pull cables.

Working tables, which also include desks or workbenches, are known,which consist of a metal frame, which supports what is known as theworktop. In this connection, the frame consists to begin with of a lowerframe, which consists of at least two outer tubes which are connected ata distance via a strut and can have a different cross-sectional shapeand cross-sectional size. Inner tubes, which are interconnected eitherexclusively via the worktop or, if necessary, additionally via a strutas well, are then guided displaceably in the outer tubes. In thisarrangement, in each case one outer tube and one inner tube form asupport leg of the working table. In order for it then to be possible tovary, or increase, the height of the worktop, a cable is in each caseconnected in the upper region of the lower frame, preferably in theupper region of the outer tube, which cable is guided to the lower endof the inner tube, deflected there, guided upward again, subsequentlyextends, in the upper region of the outer tube, into the lower frame andis there taken up by a tension unit, which may be designed as, forexample, a cable drum. In this arrangement, all the cables of thesupport legs are connected to the tension unit. By appropriate movementof the tension unit, the inner tubes are then gradually, but withinpredetermined limits, pushed out of the outer tubes, so that the worktopis raised. With an opposite movement of the tension unit, the pullcables are slackened again, and the inner tubes move back into the outertubes owing to the weight, in particular of the worktop. In thisconnection, the tension unit can be moved either by hand or via aspecial drive.

Such working tables are relatively complicated and expensive tomanufacture. This is connected in particular with the fact that theouter and inner tubes forming the support legs are special profiles andhave to be guided very accurately in one another via special slidingpieces. Owing to the design of the upper and lower frame, the workingtable is always ready-assembled before it is delivered, which involveshigh transport costs. Such a working table is furthermore relativelyheavy, which is disadvantageous in terms of setting it up.

The object of the invention is to produce a working table with aheight-adjustable worktop, which has a relatively low weight and is veryinexpensive. The working table is moreover to be designed in such a waythat it can easily be dismantled into its component parts, can be packedin a small space and can be assembled without difficulty by a layperson.

According to the invention, a working table according to claim 1 isproposed in order to achieve this object.

A working table of such design has relatively low weight with greatstability and can be manufactured inexpensively. Standard tubes can beused for the guide rails, so that no special fabrication is required.Dismantled into component parts, the working table can be packed in abox with a small space requirement, be stored at low cost and thus alsobe transported in a space-saving way. Its design makes it possible forany layperson to assemble the working table according to the inventionwithout special technical ability. The downward movement of the worktoptakes place by virtue of its weight, so that the risk of pinching forthe user is considerably reduced. The cable guide is designed in such away that the cable never falls out of its track. The worktop can besuspended on more than two cables, which are each driven. All the drivecables are guided on a drum. The suspension point is located above thehighest table position. Preferably, the motor switches itself offautomatically when at least one cable is relieved, and/or a reversal ofthe motor takes place by means of electronic control in order to avoidtilting of the worktop or injury to the user. Various table heights canbe stored. The worktop can be of inclinable or completely fold-awaydesign.

Further features of a working table according to the invention aredisclosed in claims 2 to 9.

The invention is explained below with reference to drawings 1-14.

These explanations are only examples and do not limit the generalinventive idea.

FIG. 1 shows an embodiment of the working table according to theinvention.

FIG. 2 shows an embodiment of the drive of the worktop.

FIG. 3 a shows an embodiment of the mounting arrangement of the pullcable.

FIG. 3 b shows an embodiment of the mounting arrangement of the worktopon the guide rail.

FIG. 4 shows the arrangement of the motor on the tabletop.

FIGS. 5-14 show further embodiments of the working table according tothe invention.

FIG. 15 shows a further embodiment of the working table according to theinvention.

FIG. 1 shows a working table 1 according to the invention in a lateralelevation in section, the section running parallel to the narrow side ofa worktop 2. The working table 1 consists of two vertically extendingguide rails 3, which, in the illustrative embodiment shown, are made assupport legs, are arranged at the rear side of the worktop 2 and areeach made from a rectangular tube and advantageously have a square crosssection. Other cross-sectional shapes can of course also be selected. Inthis connection, it is expedient as far as possible to use suchcross-sectional shapes as are available on the market as standard tubesand do not make special fabrication necessary. The outer cross-sectionaldimension of the support legs 3 is roughly 40 to 50 mm. In the lowerregion of each support leg 3, two struts 4, 5 running at an angle to thesupport leg 3 are connected, for example by welding, which likewiseconsist of a commercially available tube, which run at an angle ofroughly 90° to one another and via which the support leg 3 is supportedon the floor. The support leg 3 is consequently designed in one piecewith the two struts 4, 5.

The two support legs 3 designed in one piece with the struts 4, 5 inthis way are interconnected firmly but disconnectably by a metal sheet 6having an L-shaped cross section. This connection takes place by meansof screws 7, as indicated in the drawing. These screws 7 are insertedinto what are known as gusset plates 8, which are located in the metalsheet 6. It is also possible, however, to interconnect these partspositively, for example by “hooking-in”. This disconnectable connectionmakes it possible to dismantle the working table 1 and then to pack thesupport legs 3 with the struts 4, 5 in a very small space. During actualassembly, therefore, the two support legs 3 are first erected andinterconnected via the metal sheet 6. This results in a stable,supporting unit. The metal sheet 6 having an L-shaped cross section canbe used as what is known as a cable duct.

The working table 1 also has two crosspieces 9, which are folded in aU-shape from sheet metal with a wall thickness of 2.00 to 4.00 mm andare downwardly open. At their rear ends, the web of these crosspieces 9is notched, so that in each case a crosspiece 9. can be pushed on over asupport leg 3 from above. The two crosspieces 9 are firmlyinterconnected by a U-shaped sheet 10 with a wall thickness of 1.50 to3.00 mm. This connection can in this case be made in the factory and beof disconnectable or non-disconnectable design. For packing of theworking table 1, however, this connection does not have to be undone, asthe area of this unit is not greater than the overall area of thesupport legs 3. In order for it then to be possible to move and thusraise and lower the two crosspieces 9 on the support legs 3, eachcrosspiece 9 has an upper, rear roller 11 and a lower, front roller 12,which rollers are, for example, formed by a ball bearing and heldrotatably between the legs of a crosspiece 9 and bear against a supportleg 3. In addition, a sliding piece likewise bearing against thevertical support leg 3 is provided on each lateral leg of thecrosspieces 9, so that good, secure guidance of the crosspieces 9 on thesupport legs 3 is ensured.

The U-shaped sheet 10 is inserted, open upwardly, between the twocrosspieces 9 and accommodates a drive motor known per se with a shaftand with at least one cable drum with two pull cables 13 guided viadeflection rollers. The arrangement of two cable drums is also possible.These parts are known per se and have therefore not been included in thedrawing.

As soon as the assembly described above has been carried out, the freeends of the pull cables are each attached at an upper end of the supportlegs 3, which are designed specially for this purpose. The pull cables13 are guided in deflection rollers in such a way that they can neverleave the running groove of the deflection rollers, even when the cabletension is slackened. This is also the case when the working table 1 isdismantled for transport and the pull cables 13 are detached to thisend. After the drive motor is switched on, the two crosspieces 9 arethen simultaneously and evenly pulled continuously upward by the motoror are let down by virtue of their own weight and the weight of theworktop 2. The worktop 2, which is fastened on the two crosspieces 9 bymeans of screws, for example, can thus be raised or lowered. Thedownward movement of the crosspieces 9 and thus the lowering of theworktop 2 takes place exclusively by virtue of the dead weight of theworktop 2, crosspieces 9 and U-shaped sheet 10 with the drive partslocated therein. The drive exerts no forces of any kind on thecrosspieces 9 for this purpose. When the tension of the pull cables isslackened, the drive motor is switched off immediately via a specialswitch. The adjustment range of the worktop 2 is roughly 600 mm andmakes a working height of the worktop 2 of between 650 and 1250 mmpossible.

In modification of the illustrative embodiment explained, it is possibleto arrange the vertical tubes of the support legs 3 at the side of theworktop 2 instead of at the rear. However, the crosspieces 9 should thenas far as possible extend transversely in front of the support legs 3 inorder that sufficient stability of the working table 1 is ensured. Ifappropriate, the support legs 3 with the struts 4, 5 can then also bedesigned differently.

FIG. 2 shows a possible embodiment of the drive of the worktop 2, which,as described above, is mounted on the guide rails 3. The pull cable 13is supported with its one end at the upper end of the guide rail 3. Thepull cable is rolled up on and off from the cable drum 14 by means ofthe motor 15.

FIG. 3 a shows a preferred embodiment of the suspension 16 of the cable13 at the upper end of the guide rail. The suspension 16 consistsessentially of a plug 17, which is preferably received at least partlypositively by the guide rail 3 and is supported on its wall. The cableis arranged in the plug 17 in such a way that it can be subjected totensile loading (illustrated by the arrow). For assembly of the workingtable according to the invention, the plug 17 is pushed onto the guiderail 3, and, for disassembly, it can be removed again.

FIG. 3 b shows two views of a preferred embodiment of the mountingarrangement of the crosspiece 9 on the guide rail 3. In the presentcase, the rollers 11, 12 act on the inner cross section of the profile3, the rollers 12 being arranged at the front and the rollers 11 at therear. The expert will recognize that in this case the profile must havea slot 20, in which the crosspiece moves up and down. In addition, aroller 18, around which deflection of the cable 13 from the cable drum(not illustrated) to the mounting 16 (not illustrated) takes place, isprovided in the crosspiece.

FIG. 4 shows the mounting arrangement of the motor 15 and the cable drum14 on the worktop 2, the worktop 2 not being illustrated. The pull cable13 is conducted from the cable drum 14 via a roller 19 to the roller 18.It can be seen that two pull cables 13 run on one reel 14, so that theupward and downward movement on the two guide rails 3 (only oneillustrated) does not have to be synchronized. The expert will recognizethat it is also possible for three or more pull cables to be guided onone cable drum.

FIGS. 5-14 show possible embodiments of the working table according tothe invention. In the embodiment according to FIG. 8, the working tablehas three guide rails 3, so that the worktop is raised or lowered atthree locations. The working table according to FIG. 10 has a hinge 21,so that the worktop 2 can be folded down, and hinges 25, with which theleg extensions 26 can be folded in. In the embodiment according to FIG.11, the working table is arranged in a box in order for it to bepossible to raise or lower a television, for example. In FIG. 12, theguide rails 3 are mounted on a wall, and, in FIG. 13, the guide rails 3are made as support legs and interconnected non-positively by thecrosspiece 22. FIG. 14 shows a further embodiment of the crosspiece 22,which in the present case interacts positively with the support legs 3,which are braced together with one another by the cables 23.

FIG. 15 shows a further embodiment of the working table 1 according tothe invention. The working table 1 consists of two vertically extendingguide rails 3, which, in the illustrative embodiment shown, are made assupport legs, are arranged at the rear side of the worktop 2 and areeach made from a rectangular tube and advantageously have a square crosssection. Other cross-sectional shapes can of course also be selected. Inthis connection, it is expedient as far as possible to use suchcross-sectional shapes as are available on the market as standard tubesand do not make special fabrication necessary. The outer cross-sectionaldimension of the support legs 3 is roughly 40 to 50 mm. In the lowerregion of each support leg 3, two struts 4, 5 running at an angle to thesupport leg 3 are connected, for example by welding, which likewiseconsist of a commercially available tube, which run at an angle ofroughly 90° to one another and via which the support leg 3 is supportedon the floor. The support leg 3 is consequently designed in one piecewith the two struts 4, 5.

The two support legs 3 designed in one piece with the struts 4, 5 inthis way are interconnected firmly but disconnectably by a metal sheet(not illustrated). This disconnectable connection makes it possible todismantle the working table 1 and then to pack the support legs 3 withthe struts 4, 5 in a very small space. During actual assembly,therefore, the two support legs 3 are first erected and interconnectedvia the metal sheet. This results in a stable, supporting unit.

The working table 1 also has two crosspieces 9, which are folded in aU-shape from sheet metal with a wall thickness of 2.00 to 4.00 mm andare downwardly open. In order for it then to be possible to move andthus raise and lower the two crosspieces 9 on the support legs 3, eachcrosspiece 9 has an upper, rear roller 11 and a lower, front roller 12,which rollers are, for example, formed by a ball bearing and heldrotatably between the legs of a crosspiece 9 and bear against a supportleg 3. The expert will recognize that in this case the profile must havea slot, in which the crosspiece moves up and down.

As soon as the assembly described above has been carried out, the pullcable 13 is guided from the motor 15 via a deflection roller 30 andfastened to the crosspiece 9 in the region of the roller 12. After thedrive motor is switched on, the two crosspieces 9 are thensimultaneously and evenly pulled continuously upward by the motor or arelet down by virtue of their own weight and the weight of the worktop 2.The worktop 2, which is fastened on the two crosspieces 9 by means ofscrews, for example, can thus be raised or lowered. The downwardmovement of the crosspieces 9 and thus the lowering of the worktop 2takes place exclusively by virtue of the dead weight of the worktop 2and crosspieces 9. The drive exerts no forces of any kind on thecrosspieces 9 for this purpose. When the tension of the pull cables isslackened, the drive motor is switched off immediately via a specialswitch. The adjustment range of the worktop 2 is roughly 600 mm andmakes a working height of the worktop 2 of between 650 and 1250 mmpossible.

1. A height-adjustable working table with at least two guide rails (3)for receiving a worktop (2), which is adjustable in its working heightby means of a drive motor with at least one cable drum and pull cables,wherein each guide rail (3) is formed by a profile and the worktop (2)is mounted displaceably on the guide rails in such a way that thedownward movement of the worktop takes place by virtue of its ownweight, the drive motor (15) with the cable drum (14) being arranged inthe region of the worktop (2), and the guide rails (3) having means (16)with which in each case one end of the pull cables (13) can preferablybe attached at the upper ends of the guide rods.
 2. The working table asclaimed in claim 1, wherein the worktop (2) has a means (11,12) whichinteracts with the guide rails (3) on the inner and/or outer crosssection.
 3. The working table as claimed in claim 1, wherein the guiderail (3) is designed essentially, as a rectangular tube.
 4. The workingtable as claimed in claim 2, wherein the means is a front and a rearroller (11, 12).
 5. The working table as claimed in claim 4, wherein thefront roller (12) and the rear roller (11) each bear against the outercross section of the guide rail (3), at the bottom and at the toprespectively.
 6. The working table as claimed in claim 4, wherein thefront roller (12) and the rear roller (11) each bear against the innercross section of the guide rail (3), at the top and at the bottomrespectively.
 7. The working table as claimed in claim 4, wherein therollers (11, 12) are formed by ball bearings.